1. Field of the invention
The present invention relates to a method for assembling two assemblies together, each of which assembly has a rotating shaft member to be connected to the other rotating shaft member through a rotating medium. The present invention also relates to a rotating medium used for this method. More particularly, the present invention relates to a method for assembling, for example a cylinder block assembly of an automobile and a transmission assembly together through a rotating medium such as a torque converter.
2. Prior Art
In the process of automobile assembly, there is a need for assembling two assemblies together through a rotating medium, such as in the case of assembling a cylinder block assembly with a transmission assembly or assembling a clutch assembly. In such case, each assembly has a rotating shaft member to be connected to the other rotating shaft member through a rotating medium. Specifically, one of these assemblies is connected to the rotating medium by fitting engagement of the splines formed on the assembly and the rotating medium, respectively.
Well-known prior art method for assembling these two assemblies together will be described. By way of example, assembling a cylinder block assembly with a transmission assembly will be described with reference to FIG.5. FIG.5 is an enlarged vertical section partly showing a conventional torque converter, cylinder block assembly and a transmission assembly.
A torque converter 101 as a rotating medium is a device for the transmission of power through a fluid such as oil held in a casing. The torque converter 101 comprises a doughnut-shaped casing 101a filled with oil, a stator 101b, and two impellers 101c, 101d positioned opposite to each other around the stator 101b.
One of the two impellers 101c (hereinafter referred to as a pump impeller) is integrated with the casing 101a. When the engine is actuated, power is transmitted from the engine through a crankshaft 104, drive plate 105 and the casing 101a so as to make a flow of oil within the casing 101a. Such flow of oil is transmitted to the other impeller 101d (hereinafter referred to as a turbine runner) while it is controlled by the stator 101b. The turbine runner 101d is then rotated. The turbine runner 101d is further connected to a main shaft 102a of a transmission assembly 102 so that the main shaft 102a is rotated by the rotation of the turbine runner 101d. Accordingly, when the engine is actuated, rotation of the pump impeller 101c is transmitted through oil to the main shaft 102a, thereby rotating the main shaft 102a.
In such torque converter 101, since the pump impeller 101c, stator 101b and the turbine runner 101d are rotated independently, separate spline portions 106a, 106b, 106c are provided at the respective center portions thereof.
The transmission assembly 102 is provided with a first, second and a third spline portions 107a, 107b, 107c for fitting engagement with the corresponding spline portions 106a, 106b, 106c of the torque converter 101. The first spline portion 107a is formed at a position where the transmission assembly 102 is connected to the pump impeller 101c through a bearing 102b. The second spline portion 107b is formed at a position where the transmission assembly 102 is connected to the stator 106c around the main shaft 102a. And the third spline portion 107c is formed at the front side of the main shaft 102a so as to connect the main shaft 102a and the turbine runner 101d. Here, the main shaft 102a is the rotating shaft member of the transmission assembly 102.
Known method for assembling the transmission assembly 102 and the cylinder block assembly 103 together will be described. The cylinder block assembly 103 holds the crankshaft 104 at a journal portion (not shown). The drive plate 105 is then mounted at the end of the crankshaft 104. Here, the crankshaft 104 and the drive plate 105 form the rotating shaft member of the cylinder block assembly 103.
At first, the torque converter 101 is fixed to the drive plate 105 through a plurality of bolts 105a, 105a. To this end, a mounting bracket 101e of the torque converter 101 is provided with bolt holes 101f and the drive plate 105 is also provided with corresponding bolt holes 105d. When the torque converter 101 is fixed to the drive plate 105, a plurality of bolts 105a, 105a are inserted from the drive plate 105 and they are screwed between the drive plate 105 and the torque converter 101.
Secondly, the transmission assembly 102 is assembled with the cylinder block assembly 103 with the first, second and the third spline portions 107a, 107b, 107c of the transmission assembly 102 fittingly engaged with the corresponding spline portions 106a, 106b, 106c of the torque converter 101. When assembling, phase adjustment is carried out between each first, second or third spline portion 107a, 107b, 107c of the transmission assembly 102 and the corresponding spline portion 106a, 106b, 106c of the torque converter 101, and then the transmission assembly 102 and the cylinder block assembly 103 are assembled together by the fitting engagement of these spline portions. In such position, a mounting surface 102c provided at the circumferential end of the transmission assembly 102 abuts on an attachment surface 103a of the cylinder block assembly 103 so that the corresponding bolt holes 102d, 103b are met each other. A plurality of bolts 108, 108 (only one bolt 108 is shown in FIG. 5) are screwed within the bolt holes 102d, 103b, and the transmission assembly 102 and the cylinder block assembly 103 are assembled together.